Can anyone explain to me exactly (in detail) how the different varieties of valve rotators work? A link would also work, I'm too lazy to sift through Google results (as most will probably end up being parts websites or forum posts). I have the book 'Auto Fundamentals' (very good book, I recommend it to anyone), which is usually very thorough in thier explainations, but with valve rotators they're very vauge.

Also, on a different matter... does anyone have any diagrams/descriptions of any EJ series head? I'm just curious as to what they look like, and I'm not going to tear mine off to find out